Anticancer Potential of Calli Versus Seedling Extracts Derived from Rosmarinus officinalis and Coleus hybridus

Background: In Saudi Arabia, the incidence and mortality rates of breast cancer are high. Although current treatments are effective, breast cancer cells develop resistance to these treatments. Numerous studies have demonstrated that active compounds in plant extracts, such as the phenolic compound Rosmarinic Acid (RA), exert anti-cancer effects. Objective: We investigated the anticancer properties of methanolic crude extracts of seedlings and calli of Rosmarinus officinalis and Coleus hybridus, two Lamiaceae species. Methods: MCF-7 human breast cancer cells were treated with methanolic crude extracts obtained from plant calli and seedlings generated in vitro, and cell proliferation was evaluated. Transcriptional profiling of the seedling and callus tissues was also conducted. Results: The mRNA expression levels of RA genes were higher in C. hybridus seedlings than in R. officinalis seedlings, as well as in C. hybridus calli than in R. officinalis calli, except for TAT and C4H. In addition, seedling and callus extracts of both R. officinalis and C. hybridus showed anti-proliferative effects against MCF-7 cells after 24 or 48 h of treatment. Discussion: At a low concentration of 10 μg/mL, C. hybridus calli and seedling extracts showed the most significant anti-proliferative effects after 24 and 48 h of exposure (p < 0.01); controls (doxorubicin) also showed significant inhibition, but lesser than that observed with C. hybridus (p < 0.05). Results with R. officinalis callus and seedling extracts did not significantly differ from those with untreated cells. Conclusion: Methanolic extracts of R. officinalis and C. hybridus are potentially valuable options for breast cancer treatment.